Method for Separating Liquid From Suspended Matter in a Sludge and Device for Same

ABSTRACT

The invention relates to a method for separating the liquid part from the suspended matter in a sludge supplied in a continuous flow at a flow rate of Q EB =V/hour. The flow is divided into at least two partial flows which are sprayed on top of one another into a sealed chamber of volume v&lt;V/ 20 , simultaneously injecting air therein at a flow rate d, said chamber being kept under overpressure conditions. The suspended matter of the thus treated flow is then left to decant in a collection container, with the cake or solid part falling to the bottom and separating from the liquid part which is continuously discharged.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of prior U.S. application Ser. No.13/881,561, filed Apr. 25, 2013, now U.S. Pat. No. 9,890,068, which is aU.S. national stage of PCT/FR2011/000582, filed Oct. 28, 2011, thecontents of which are incorporated herein by reference.

FIELD

The present invention relates to a method for separating the liquid partand the suspended matter of a sludge fed in continuous flow at a rateQ_(EB)=V/hour.

The invention thus allows elimination of virtually all of the suspendedmatter, in order to take this matter beneath a specified threshold.

The invention likewise relates to a device for sludge treatment thatimplements such a method.

The invention finds particularly significant, though not exclusive,application in the field of sludge dewatering and water clarification.

The invention results, surprisingly, from the use of a very high energyin a liquid, sludgy medium, which will in particular allow the colloidalstructures within such an effluent to be attacked.

BACKGROUND

Colloids are present, indeed, in solid sludges (in their organicfraction), but also in waters.

It is these colloids in particular which cause a turbid coloration andwhich hinder the separation of solid and liquid phases and thedecoloring of certain waters.

There are methods known for separating solid matter in suspension fromthe liquid effluent in which it is located.

The techniques in existence for extracting water from sludges areessentially compacting, which increases the solid-compound content (in %by weight of the total mixture) by an order of 5%; centrifuging orfiltration, which each increase the solid-compound content by 18 to 25%;and, lastly, drying (by combustion or spreading for a number of weeks),which increases the solid-compound content by 90 to 95%, bearing in mindthat the amount by weight of solid compound in treatment sludges priorto processing is in general between 0.1 to 1% of the total weight of theeffluent.

All of these known treatments from the prior art have disadvantages,associated either with the insufficient drying (compacting,centrifuging, filtration) or with the treatment time (drying) or withthe substantial consumption of energy (combustion).

Likewise known (FR 73.08654) is a method for treating sludge wasteswherein a watertight circuit comprising a tank, in which recirculationtakes place for a number of tens of minutes, is fed with a gascontaining oxygen in the circuit upstream of the tank.

Retention of the activated sludge in the tank for a period of timesufficient to allow supersaturation by the gas containing oxygen isindicated as allowing the substantial removal of the solids insuspension.

A method of this kind, as well as being long, employs a fairlycomplicated device, which is a source of numerous clogging events.

SUMMARY

The present invention aims to provide a method and a device which are abetter response than those known to date to the practical requirements,particularly in the sense that the invention will allow advanceddewatering, much better than that obtained with the existing techniques,whether employed alone or in combination with such techniques, and willdo so very rapidly, since the use of the method according to theinvention requires only a few seconds to produce a result.

More particularly, this method allows excellent results to be obtainedon its own for highly mineralized sludges (that is, sludges having a %of organic matter in 100% by weight of dry matter of less than from 5 to15%).

With less mineralized sludges, it is possible to obtain an optimizedyield when the method is combined with a complementary separation tooldownstream of the device (belt filter or centrifuging), enhancing solidsincrease by more than 10%, as for example by 25%.

Existing plants can therefore be easily enhanced by addition of one ormore reactors that implement the invention, and this, subsequently andfor example, will save on the costs of transport and final incinerationof the sludges.

The invention, furthermore, exhibits very low electrical consumption anddoes not use very much consumable material (compressed air, additive).

Moreover, the method employs a simple and very compact device which iseasily transportable and which will therefore be able to be installed onsites without easy access.

Continuous operation is possible with the invention, with very relaxedconstraints on exploitation.

The processing according to the invention, furthermore, does not giverise to any pollution, while employing a technique which is itself muchmore economical than those known in the field of liquid/solid separation(centrifuge, press filter, belt filter, continuous oxygenatedrecirculation, etc.).

Lastly, the invention, surprisingly, produces a new type of porousdewatered cake that constitutes a useful residue.

For this purpose, the invention particularly provides a method forseparating the liquid part and the suspended matter of a sludge that arefed in continuous flow at a rate Q_(EB)=V/hour, wherein the air isinjected at a rate d, characterized in that the flow is formed from atleast two partial flows, which are sprayed onto one another in a closedchamber of volume v<V/20, for passage of the flow under pressure, theair being injected into the chamber which is maintained at a pressuregreater than a specified value, after which filtration takes place orthe suspended matter of the flow thus treated is left to settle in acollection container.

The closed chamber is fed and evacuated continuously at the same rate orsubstantially at the same continuous inlet and outlet rate of theeffluent.

The chamber therefore constitutes an in-line accident of the treatedflow without loop recirculation of the effluents to the interior of thechamber.

Advantageously, in the case of settling, the solid part or cake falls tothe bottom part of the container, separating from the liquid part, whichis discharged continuously.

By closed chamber is meant a tank or a reactor of predetermined closedvolume, but, and of course, comprising the means for entry of thecontinuous flow, and means for exit (generally a tube) of saidcontinuous flow after treatment, at the same rate or substantially atthe same rate.

The chamber is therefore a chamber for passage of the flow underpressure.

By a value v<V/20 is meant a lower or an approximately lower value, witha tolerance of the order of ±10% to 20%.

Advantageously v≤V/25 or ≤V/30.

In one advantageous embodiment of the invention the excellent resultsare attained in particular by virtue of the combination of a pluralityof functions in the same small-sized chamber, by provision of fourfunctional zones:

A zone for introduction of slightly compressed air, this zone alsohosting suspension, or prevention of settling, of the heaviestparticles, which are nevertheless capable of rising within the reactorand of emerging at the top part with the finest particles.

A hydraulic impact zone in which the liquid flows are introduced.

A rise zone of the bed, consisting, for an amount by weight ofapproximately 1 of gas, of 0.1 of water and of 0.01 of solid. Withinthis zone, very vigorous agitation is made possible by the provision ofair of the recommended quality (rate and pressure).

A decompression zone, regulated for example by a slide valve situated atthe top part of the reactor. In the example of this slide valve, it isrequired to maintain the reactor at a relative pressure of approximately0.5 to 2 bar.

In advantageous embodiments, moreover, one and/or other of the followingarrangements is employed:

-   -   the flow is injected into the chamber of volume v<V/20 via two        identical opposite orifices situated in the lower half of said        chamber, the air being injected below said orifices, and the        flow is removed continuously or intermittently at the top part,        by means, for example, of a pressure relief valve that releases        above a specified threshold value;    -   the air is injected at a rate d>1.5 Q_(EB), as for example        greater than 5 Q_(EB), than 10 Q_(EB), or of between 1.5 times        and 15 times Q_(EB);    -   the air is injected at average pressure. By average pressure is        meant between 1.4 bar and 2.5 bar, advantageously between 1.6        bar and 1.9 bar. Such a pressure generates larger bubbles, which        will be able to penetrate the medium more effectively, by being        distributed randomly within the chamber.    -   the collection container is discharged permanently by overflow;    -   v≤V/50;    -   v≤V/100;    -   the rate Q_(EB) is greater than or equal to 15 m3/h, the rate d        is greater than or equal to 25 Nm3/h, and the relative pressure        in the chamber is greater than or equal to 0.8 bar;    -   the rate Q_(EB) is greater than or equal to 20 m3/h, the rate d        is greater than or equal to 50 Nm3/h, and the relative pressure        in the chamber is greater than 1.2 bar;    -   at least one liquid reagent is added continuously at a rate q to        the interior of the chamber;    -   the reagent is added in proportions of between 0.05% and 0.1% of        the dry matter content of the sludge. By dry matter content is        meant the % by weight of solid over the total % by weight of the        effluent;    -   the liquid reagent is a cationic organic flocculant;    -   the effluents are degassed on emergence from the chamber, and        the gases obtained are used to feed the injection of air in the        bottom part;    -   the resulting cake is recovered and dewatered by drying,        pressing, or centrifuging, to give a solidified pancake.

The invention also provides a product obtained directly by the method asdescribed above.

It likewise provides a solidified sludge pancake obtained with themethod described above, this pancake being characterized in that it hasa porosity of between 5% and 15%.

The invention also provides a device employing the method as describedabove.

It further provides a device for separating the liquid part and thesuspended matter of a sludge that are fed in continuous flow at a rateQ_(EB)=V/h, comprising means for feeding with air at a rate d, and acontainer for collecting and settling the suspended matter of the flowthus treated, and also means for continuously evacuating the supernatantliquid part of said flow to the exterior of said container,characterized in that said device comprises

-   -   a closed chamber of volume v<V/20 which comprises at least two        identical opposite orifices situated in the lower half of said        chamber,    -   means for catching the sludge and feeding the flow of sludge        thus caught into said chamber in at least two partial flows        each, respectively, injected via one of said orifices,    -   the means for feeding with air at a rate d being suitable for        injecting the air into the chamber below said orifices, and    -   means for removing the flow continuously or intermittently, the        pressure in the chamber being greater than a specified threshold        value.

The device is advantageously arranged so that the flow is removed at thetop part by means of a pressure relief valve which releases above saidspecified threshold value.

Likewise advantageously, the means for continuous removal of thesupernatant liquid part are formed by a gravitational overflow device.

In one advantageous embodiment v≤V/50.

Likewise advantageously v≤V/100.

The invention also provides a device wherein the means for feeding aliquid reagent, at a specified rate, directly into the chamber areprovided.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood from a reading of thedescription that follows of embodiments which are given as nonlimitativeexamples. The description makes reference to the accompanying drawings,in which:

FIG. 1 is a scheme of principle illustrating the processing methodaccording to the invention.

FIG. 2 is a scheme of operation of one embodiment of a device accordingto the invention.

FIG. 3 is a view illustrating schematically the conversion of a sludge,using a device according to one embodiment of the invention.

DETAILED DESCRIPTION

FIG. 1 shows the principles of the method for separating liquid andsolid in a sludge, according to the embodiment of the invention moreparticularly described here.

In a reactor 1 formed by an oblong chamber 2 which extends about an axis3, and has a small volume v of the order, for example, of 50 liters, theeffluents (arrows 4) are injected via two opposite ports 5, 6 which aresymmetrical with respect to the axis 3 of the chamber.

The ports are situated at the bottom part of the chamber, as for exampleat a distance h from the base 7 of the chamber, between one fifth andone third of the height H of the chamber.

These two ports, situated opposite one another, allow a pressurized feedof the flow of water highly loaded with dry matter (DM) (for example, τof DM 10%/total weight), giving rise to a substantial impact at thepoint where the two flows meet in the zone 8.

In other words, the pumping of the waters from the outside (not shown)that are introduced into the chamber of the small-sized reactor 1, viathe two opposing ports, produces an impact between the flows in the zone8, owing to the outlet pressure of the feed pump or pumps (not shown),which is dependent on the height of water in said feed pumps upstream ofthe ports, and on the head losses in the circuit.

Conventionally, using commercial industrial pumps and a circuit withoutexcessive aberrations, a pressure of 2 bar at the outlet 9 of the portsinto the chamber is readily attainable.

The kinetic energy of pumping is then converted into impact energy,which is maximized by increasing the velocity of introduction into thechamber for the outlet of the ports of regulator jets 9 of reduced size,but compatible with the maximum particle size of the sludge.

Furthermore, and according to the embodiment of the invention moreparticularly described here, an amount of pressurized air (arrow 10) isintroduced below the zone 8.

By pressurized is meant a slight overpressure, which may be between 0.1bar relative and 1 bar relative in relation to the atmospheric pressure,as for example 0.8 bar relative.

This air is introduced via an air distribution ramp 11, as for example aramp formed by a circular, coiled or rectilinear pipe, allowing bubblesof air to be introduced with distribution over the surface of thechamber, via orifices 12 which are spread along said pipe 13.

The air may also be brought via a port at the bottom part.

The ramp is situated below the meeting point of the effluents in zone 8,as for example between one tenth and one fifth of the height H of thechamber, and produces large bubbles B, with a bubble diameter, forexample, of between 1 mm and 1 cm.

This introduction of air increases the energy level in the chamber,which is in overpressure in relation to its outlet 14 for removal of theeffluents after processing.

Also obtained, in upper part 15 of the chamber, is a functional zone 16,in which extremely turbulent mixing, featuring Brownian motion (dashedline 17), is realized.

At the bottom part 18 of the reactor, conventionally, a purge 19 isprovided for elements which are too dense, which do not escape via thetop of the reactor, this purge being emptied sequentially.

Escaping at the outlet 14 of the reactor are the air, the water, and thesludges, to give, after settling, transparent water which is physicallyseparate from the solid material, with a very low solid matter content,in particular of less than 30 mg/l or even than 10 mg/1, while initiallythe solid matter content could have approached more than 500 mg/l.

The decolloidized solid matter obtained at this point is more porousand, consequently, is readily compactable. Depending on its initiallevel of organic matter, it may even be directly pelletizable onemergence from the reactor.

The air is introduced at an average pressure, for example, of between1.6 bar and 1.9 bar absolute to the pressure in the chamber itself, sothat there may be large bubbles in the mixture, which will be able topenetrate the mixture and become distributed randomly within thereactor, to produce the expected mixing.

The air is introduced, moreover, at a high rate d, in other words of 1.5times to 15 times (in Nm³/h) the rate Q_(EB) of the incoming water (inm³/h).

The gas extracted from the reactor emerges with the water and the sludgeat the rate of the pressure booster, and can be recovered, processed,and, where appropriate, recycled for use again at the bottom part of thereactor.

It should be noted that the presence of coarse matter, of the sand,gravel, etc., type, increases the number of impacts and, consequently,enhances the process.

The pressure of the chamber, in turn, is arranged and/or regulated insuch a way as to optimize the internal energy by generating an ascendingflow emerging from the top.

Such a pressure is therefore specified as a function of the functionalfeatures of the circuit (height of water in pumps), but also of the typeof effluents and the desired processing rates.

The size eventually selected for the reactor will also be specified bythe skilled person as a function of the basic knowledge of an engineerin the field of chemical engineering, and of the diagram of the flows.

The pressure and the emergence are ensured, for example, by means of aslide valve which releases the flow when the given pressure is exceeded.

Since the method according to the invention employs stirring in threephases—solid, liquid, and gaseous—it is necessary at the outlet to carryout separation that takes account of the degassing, of thedenser-than-water solid phase, and of the removal of the water.

In one advantageous embodiment, in addition, a coagulant is added (e.g.,lime, ferric chloride).

This complementary addition is made, for example, in the functional zone16.

Accordingly, with a reactor having a diameter of 55 liters and injectionnozzles into this reactor with a diameter of 40 mm, up to 20 m³/h ofsludge can be processed.

Surprisingly it is observed, furthermore, with the method of theinvention that when the pressure in the reactor is greater in terms ofrelative pressure than 0.8 bar, the feed rate Q_(EB) of the sludgy waterformed, for example, by spreading slurries with a DM load of 5%, said DMbeing obtained from the biodegradation of swamp grass, clay, sand, andvarious petroleum residues at trace levels (<1%), is greater than 15m³/h, and when the air rate d is greater than 25 m³/h, exceptionalseparation is obtained, with a maximum settling rate of a sludge which,after drying, has a new, porous, granular appearance.

With a 55 liter reactor and with 40 mm nozzles for injecting theeffluent within, percussion velocity values are obtained that areextremely rapid, and residence times in the reactor are obtained thatare particularly short [cf. table I below].

TABLE I m³/h Effluent 1 2 3 4 5 6 7 10 15 20 flow m/s Percussion 0.1110.221 0.332 0.442 0.553 0.774 1.105 1.658 2.210 velocity, solidparticles s Residence 198.00 99.00 66.00 49.50 39.60 28.29 19.80 14.859.9 time, reactor

By virtue of the invention it is therefore possible to obtain advanceddewatering much better than that obtained by virtue of the existingtechniques, and within a few seconds.

By way of example, table II below reports the improvement Δ in solidsobtained with the method according to the invention for a sludge fromthe Fos sur Mer industrial treatment station, this sludge having a lowmineral content (90% of organic matter), in the field of petrochemicals.

The comparison is between a simple treatment on a belt filter (with afiltering cloth on which the water and sludge are removed by pumping andconveyed between squeeze rolls), and the same belt filter afterpretreatment with the method according to the invention.

For a chamber volume v=55 l, variations were made in the parameters ofsludge rate Q_(EB) (m³/h), gas rate d(Nm³/h), and relative pressure Pinside the chamber (bar), for a specified DM load at the inlet of thechamber (in g/l).

The results are also given in dependence on the initial condition of thesludges—that is, fresh (without settling), not very fresh (aftersettling for a day), or fermented (several days of settling in theabsence of oxygen).

It is seen that a high gas rate (eight times the sludge rate) and a highpressure in the chamber (1.3 bar) enhances solids by 48.8% (trial #10)for a fairly low initial load (DM of 8.2 g/l).

On average (see trials #13 to 16) for a fresh sludge loaded at 32.4 g/lfor a gas rate twenty times greater than that of the sludges, and apressure of 1 bar relative in the chamber, the method according to theinvention increases the solids (dry matter (DM) content by weightrelative to the total weight of the sludge, i.e.: DM+liquid) from 24 to36.4%, or on average 30%.

TABLE II Rate Chamber Industrial Q_(EB) pressure Inlet Δ Trials sludgetype, sludge d gas P DM solids Outlet # Fos sur Mer m3/h Nm3/h bar g/l %% 1 not very fresh 2.8 40 0.5 24 14.7 2 not very fresh 2 50 0.8 24 20 3not very fresh 3 60 1.4 28 35.5 4 not very fresh 2 60 1 26 22.1 5 notvery fresh 2 60 1 26 21.1 6 not very fresh 2 60 1 26 20.4 7 fresh 1.5 601.1 26 26.6 8 fresh 1.3 60 1 26 22.2 9 fresh 1.2 60 0.8 26 24.4 10fermented 8 60 1.3 8.2 48.8 11 fermented 6.2 60 1.1 11 32 12 fermented 370 0.8 24 26.2 13 fresh 3 60 1 32.4 24 14 fresh 3 60 1 32.4 26 15 fresh3 60 1 32.4 36.4 16 fresh 3 60 1 32.4 30.1 17 fresh 4.4 40 1.6 32.4 27.218 fresh 5.6 50 0.9 32.4 33 19 not very fresh 6.5 60 0.5 24 28.2

Shown subsequently in table III is an example of results obtained with asingle device (without complementary treatment) on sediments (highlymineralized sludge) and with a complementary treatment (belt filter).

The treatment with the invention alone is to be compared with the beltfilter alone, which does not exceed an improvement in solids of 15 to18%.

Excellent results are obtained here even without complementary treatmentwith filter or centrifuge.

TABLE III Industrial Rate Chamber sludge Q_(EB) pressure Inlet Δ Trialstype, Fos sludge d gas P DM solids Outlet # sur Mer m3/h Nm3/h bar g/l %% 20 sediments 1.3 60 1.1 130 61.6 21 sediments 1.2 60 1.1 84 56.7 69.522 sediments 1.3 70 1 84 43.2 67.1 Alone Alone + Filter

In addition to this appreciable time gain in the treatment, very lowconsumption of electricity, of compressed air, and/or additives arerequired.

The low bulk of the chamber, furthermore, makes it readilytransportable, and allows it to be installed in sites where access isdifficult, while ensuring continuous operation in great simplicity.

The treatment according to the invention does not give rise to anypollution, and achieves this with a much more economical installation ascompared with the other treatment systems to which consideration may begiven for the task of liquid/solid separation alone, these beingcentrifuges, press filters, belt filters, etc.

Shown in FIG. 2 is an operating scheme for a device 20 in accordancewith the embodiment of the invention more particularly described here.

The device 20 allows separation of the liquid part from the dry matterof the sludge fed at 21 in continuous flow at a rate Q_(EB)=V/h, thefeeding at 21 subsequently dividing in two to feed the ports 22.

More specifically, the device 20 comprises a closed, stainless steelchamber E with a volume v<V/20, for example of 55 liters for a rateQ=V/h of 1.5 m³/h, comprising at least two identical opposite orificesor ports 22, situated in the lower half 23 of the chamber, at a distancefor example which is equal to one third of the height of the chamber.

The chamber is composed for example of a cylindrical part 24 which isterminated at the top part and at the bottom part by two identicalconical zones 25, with angles at the vertex of the order of 120°, forexample.

Each end is itself terminated by an upper tube 26 and lower tube 27. Thelower tube 27 is connected to a pipeline 28, equipped with a slide valve29, for intermittent removal of the suspended material 30 which wouldhave been settled, in the base 27 of the chamber.

The device 20 further comprises means 31 for feeding air 32 to thechamber at a rate d below the orifices 22.

This feeding takes place, for example, by way of a rectilinear pipe ortube 33, with a small diameter, of 5 cm in diameter for example, andwith a length substantially equal to the diameter of the cylindricalchamber, comprising regularly spaced nozzles 34, for exit of thecompressed air into the chamber in a distributed way, creatingsubstantial bubbles which will give rise to substantial agitation(swirls 35).

Means 36, known per se, for feeding a liquid reagent 37, a coagulant,for example, are provided. These means are formed, for example, by astorage vat 38, which feeds—by means of a metering pump 39 and aremote-controlled slide valve 40—the interior of the chamber above theports 22, in the turbulence zone.

The device 20 further comprises means 41 for removing continuously theliquid that has penetrated the chamber, by way of a slide valve or othervalve 42, which opens above a specified pressure in the chamber, of 1.3bar for example.

It is also possible not to provide a slide valve, with the circuitdownstream itself constituting the head loss required to maintain thechamber in relative overpressure.

The effluent 43 is then removed at the top part, ending up in a settlingvat 44 which is known per se.

For example, this settling vat 44 is composed of a cylindrical tank 45into which the removal pipe 46 opens below the operating level 47, inorder to limit turbulences.

The vat 44 itself discharges via overflow at 48, through a nonturbulentside tank portion 49, which is separated from the rest of the tank by anopenwork wall by location.

The decanted solid matter 50 is removed at the bottom part 51, and canbe processed subsequently.

FIG. 3, in a plan view, shows the device 20 of FIG. 2 which, from thesludge 52, produces the pancake 53, according to the invention.

In the remainder of the description, the same references will be used todenote the same elements.

Starting from the sludge or effluent 52 loaded with suspended material,which is pumped into an environment 54 by means of a pump 55 having awater level H_(o) at a rate Q_(EB), the chamber E is fed by way of thetwo ports 22 which are situated opposite, facing one another. At eachport, therefore, the rate is divided by two Q_(EB)/2.

The feed of air 32 is made below the ports, as described above, via aport 56.

A reagent (coagulant such as ferric chloride, or lime), which is knownper se and should be adapted by the skilled person depending on theeffluents processed, is fed continuously into the chamber E from the vat38 via the metering pump 39.

Following processing in the chamber as described above, the effluentsare removed at the top part, at 41, to give the defragmented,decolloidized effluent 57 as shown schematically in FIG. 3.

This decolloidized and defragmented effluent is then fed into thesettling vat 45. Following settling, which takes place continuouslywithin several seconds, the water then observed at 58 is extremelyclear, transmitting, for example, 99% of the light, or even 99.5%.

At 59, following possible complementary compacting treatment at 60, aparticularly advantageous sludge pancake is obtained, which is aeratedand solidified and has an excellent porosity of between 5% and 15%.

A product of this kind obtained with the method according to theinvention is new and will form matter for subsequent uses, as top soil,as a raw material in construction, etc.

With reference to FIG. 3, a description will now be given of theoperation of a treatment regime in accordance with the embodiment of theinvention more particularly described here.

From an environment, for example a stream 54 loaded with sludge 52, thissludge is extracted by pumping (55).

In one application example, the level of sludge, i.e., the percentage ofdry matter in terms of solid material, is for example between 3 and 10%.

This sludge feeds the chamber E, for example of volume V=100 l, at arate for example of between 5 and 50 m³/h, for example 15 m³/h.

As described above, this effluent is injected into the reactor via thetwo opposite ports 22. Simultaneously, air is fed via the lower ramp 33of the reactor, with a rate greater, for example, than 25 Nm³/h.

The pressure within this reactor is between 0.3 and 1.5 bar relative,for example greater than 0.8 bar relative, depending on the water levelof the pump and/or pumps which feed the effluents, and also on the headloss created by the chamber itself and by the removal slide valve 42which is situated at the top part of said chamber.

The pressure within the reactor may in particular be regulated by meansof this upper slide valve or other valve.

The effluent, thus agitated and fed with air, remains in the reactor fora period corresponding to the relative ratio between the rates, thevolume, and the pressure.

It is therefore retained, for example, for a residence time of severalseconds, for example of less than 1 minute, before being removed.

This time may even be very much less, since with an effluent rate ofgreater than 20 m³/h, residence within the chamber may for example befor a time of less than 10 seconds.

The sludge feed rate itself has a direct action on the percussionvelocity, in accordance with the table produced above, given that thecontact time and residence time in the reactor under pressure alsoaffect the rate of formation of the flocs and of their settling.

The rate of air and the effect of the pressure in the reactor are alsoelements which, with a view to the desired result, will be adapted, in amanner which is within the abilities of the skilled person.

When the sludges have been processed, they emerge from the reactor at apressure corresponding to the flow pressure of the rate of the fluid inthe pipe 43, to the settling vat 45, in which settling will take placein a manner known per se.

The water obtained as a supernatant is of a high purity and is itselfremoved continuously at 58.

The sludge obtained at the bottom part of the settling vat is removedeither continuously or discontinuously, according to specifiedperiods—for example, once a day.

The action of removing this sludge again very quickly increases itsquality, particularly with regard to its good porosity.

The treatment carried out by virtue of the method and reactor accordingto the invention therefore yields a porous dewatered cake, with therecovered sludge being empty, dry, and manipulable. A number of hoursare sufficient, as against three months in the context of the use ofso-called conventional drying, to obtain a comparable result, and thefeatures of the resulting sludge as well are much better with theinvention, since the sludge is more readily recyclable.

As will be obvious, and as also results from the text above, the presentinvention is not limited to the embodiments that have been moreparticularly described. Instead, it encompasses all variants of thoseembodiments, and especially those in which the orifices may be regulatorjets, tubes reaching into the interior of the chamber in order tominimize the distance between the outlets and increase the force of theimpacts.

1. An apparatus for extracting liquid from a mineralized sludge, whereinthe apparatus comprises: means for injecting, into a closed chamber, acontinuous flow of the mineralized sludge at a rate Q_(EB)=V/h, whereinV is a volume, wherein the closed chamber has an outlet and a volume ofv<V/20; means for, when the device is in operation, maintaining theclosed chamber in overpressure relative to atmospheric pressure; meansfor injecting, into the closed chamber, air at a rate d, wherein theinjecting of the continuous flow, the injecting of the air, the volumev, and the overpressure of the closed chamber are arranged to create aturbulent mixing of the continuous flow within the closed chamber,wherein the turbulent mixing results in a mixture; and tubular means fordischarging, from the closed chamber via the outlet, the mixture to acollection container, wherein the collection container is configured toenable the mixture to separate into solids and the liquid, and whereinthe collection container comprises means for discharging the liquidcontinuously by gravity.
 2. The apparatus according to claim 1, whereinthe rate d is greater than 1.5 Q_(EB).
 3. The apparatus according toclaim 1, wherein the means for injecting the continuous flow into theclosed chamber comprises at least two opposite orifices that are facingeach other and are situated in a bottom half of the closed chamber. 4.The apparatus according to claim 1, wherein the means for maintainingthe closed chamber in overpressure comprises an overpressure valve. 5.The apparatus according to claim 1, wherein the means for dischargingthe liquid part by gravity comprises a gravity overflow device.
 6. Theapparatus according to claim 1, wherein v is less than or equal to V/50.7. The apparatus according to claim 1, wherein v is less than or equalto V/100.
 8. The apparatus according to claim 1, further comprisingmeans for feeding a liquid reagent at a given rate into the closedchamber.
 9. The apparatus according to claim 1, wherein the rate Q_(EB)is greater than or equal to 15 m3/h, the rate d is greater than or equalto 23 m3/h, and the overpressure is greater than or equal to 0.8 bar.10. The apparatus according to claim 9, wherein the rate Q_(EB) isgreater than or equal to 20 m3/h, the rate d is greater than or equal to50 m3/h, and the overpressure is greater than 1.2 bar.
 11. The apparatusaccording to claim 1, further comprising means for degassing, via asecond outlet of the closed chamber, and directing gasses such that thegasses feed air injection at the bottom part.
 12. The apparatusaccording to claim 1, further comprising means for treating the solidsto obtain a solidified pancake.
 13. An apparatus for extracting liquidfrom a mineralized sludge, wherein the apparatus comprises: a collectionchamber; a closed chamber that has an outlet and a volume of v<V/20,wherein V is a volume; a valve that is arranged at the outlet and thatis configured to maintain the closed chamber in overpressure relative toatmospheric pressure; a transfer component between the closed chamberand the collection chamber; wherein the closed chamber is configured to:receive, via a first injection at a rate Q_(EB)=V/h, a continuous flowof the mineralized sludge, and receive, via a second injection at a rated, air; wherein the continuous flow, the air, the volume v, and theoverpressure of the closed chamber are arranged to create a turbulentmixing of the continuous flow within the closed chamber, wherein theturbulent mixing results in a mixture; wherein the transfer component isconfigured to receive, from the closed chamber via the outlet, adischarge of the mixture and provide, to the collection container, thedischarge of the mixture; and wherein the collection container isconfigured to: enable the mixture to separate into solids and theliquid, and discharge, via gravity, the liquid continuously.
 14. Theapparatus according to claim 13, wherein the rate d is greater than 1.5Q_(EB).
 15. The apparatus according to claim 13, wherein the closedchamber is configured to receive the continuous flow of the mineralizedsludge via at least two opposite orifices that are facing each other andare situated in a bottom half of the closed chamber.
 16. The apparatusaccording to claim 13, wherein the valve comprises an overpressurevalve.
 17. The apparatus according to claim 13, wherein v is less thanor equal to V/50.
 18. The apparatus according to claim 13, wherein therate Q_(EB) is greater than or equal to 15 m3/h, the rate d is greaterthan or equal to 23 m3/h, and the overpressure is greater than or equalto 0.8 bar.
 19. An apparatus for extracting liquid from a mineralizedsludge, wherein the apparatus comprises: means for injecting at leasttwo partial flows of the mineralized sludge into a closed chamber,wherein the at least two partial flows form a continuous flow having arate Q_(EB)=V/h, wherein V is a volume, wherein the closed chamber has avolume of v<V/20; means for injecting air into the closed chamber,wherein the injecting of the at least two partial flows and theinjecting of the air causes (a) a turbulent mixing of the at least twopartial flows that results in a mixture and (b) an increase of aninternal pressure of the closed chamber; means for discharging, via anoutlet of the closed chamber and after the internal pressure of theclosed chamber has exceeded a threshold pressure, a portion of themixture from the closed chamber and to a collection container; thecollection container configured to collect the portion of the mixture toallow for separation of solids and the liquid; and means forcontinuously discharging the liquid from the collection container. 20.The apparatus of claim 19, wherein the means for discharging comprises adischarge valve.